The long-range goal of this project is to investigate how anesthetic agents influence the renin-angiotensin system and the sympathetic nervous system in two forms of experimental hypertension in the rat. The two models of hypertension to be examined are the two kidney 1 clip renovascular model and the spontaneously hypertensive rat. The first step in the project will be to determine plasma renin activity at equipotent anesthetic concentrations and then to use specific inhibitors of the renin-angiotensin system to define the influence of this system on blood pressure during anesthesia. The second step will be to isolate the peripheral sympathetic nervous system from central influences in the intact animal through chemical ablation of descending noradrenergic and adrenergic nerves. Anesthesia will then be induced in these chronically prepared rats with and without inhibitors of the renin-angiotensin system. Important aspects of the study include: (1) quantify renin activity and function with various anesthetic agents in these two forms of hypertension, (2) assess sympathetic nervous system activity through the measurement of dopamine, norepinephrine, and epinephrine using HPLC, (3) assess the alteration in distribution of blood flow with various anesthetic agents using the microsphere method, and (4) quantify central versus peripheral sympathetic nervous system function with various anesthetic agents. The data will allow subsequent investigation of the influence of anesthetic agents in other pathologic states where hyperactivity of one or both systems is thought to exist.